This invention relates to a connector for making connections of fiber-optic, electrical, and hybrid electro-optical cables in a hostile or underwater, high pressure environment.
There are many types of connectors for making electrical and fiber-optic cable connections in hostile or harsh environments, such as undersea connectors which can be repeatedly mated and demated underwater at great ocean depths. Such underwater connectors typically comprise a plug unit containing one or more contact probes and a receptacle unit containing an equivalent number of contacts or junctions for engagement with the contact probes, which extend into the receptacle unit when the units are connected together. Typically, the contacts or junctions are contained in a sealed chamber containing optically clear dielectric fluid, and the probes enter the container via one or more openings which are sealed when the units are separated. One major problem in designing such units is the provision of seals which will adequately exclude seawater and other contamination from the contact chamber even after repeated mating and demating, and also prevent fill fluid from leaking out of the chamber.
A number of different sealing mechanisms have been proposed in the past for achieving this objective. One such sealing mechanism has an opening into the contact chamber which comprises an elastomeric tubular entrance surrounded by an elastomeric sphincter which pinches the entrance closed upon itself when the plug and receptacle units are in an unmated condition. On mating, the contact probe is forced through the opening and the sphincter pinches against the probe to form a seal. Although this type of seal is successful in some cases, it does have disadvantages. One disadvantage is that this seal does not work well under all hostile conditions. Another disadvantage is that such seals tend to lose their "memory" after repeated mating and demating, so that they may fail to close completely, or may not close quickly enough to isolate the chamber from the surrounding environment when the units are demated. Another type of known seal mechanism comprises a piston which moves axially into the seal opening as the units are demated.
In some known underwater electrical connectors, such as that described in U.S. Pat. Nos. 4,795,359 and 5,194,012 of Cairns, tubular socket contacts are provided in the receptacle unit, and spring-biased pistons are urged into sealing engagement with the open ends of the socket assemblies. As the plug and receptacle units are mated, pins on the plug portion urge the pistons back past the contact bands in the sockets, so that electrical contact is made. However, this type of arrangement cannot be used in a straightforward way for an optical connector since the optical contacts must be able to engage axially for practical purposes.
Underwater electro-optical connectors are described in U.S. Pat. Nos. 4,616,900 and 4,666,242 of Cairns. In U.S. Pat. No. 4,666,242, the male and female connector units are both oil filled and pressure balanced. This device utilizes a penetrable seal element having an opening which pinches closed when the units are separated and seals against the entering probe when mated. Other known fiber-optic connectors have similar seals which are not suitable for use under some conditions and may tend to lose effectiveness after repeated mating and demating.
Other known seal mechanisms involve some type of rotating seal element along with an actuator for rotating the seal element between a closed, sealed position when the units are unmated, and an open position when the units are mated, allowing the contact probes to pass through the seal elements into the contact chambers. Such connectors are described, for example, in U.S. Pat. Nos. 5,685,727 and 5,738,535 of Cairns. These overcome some of the reliability problems of penetrable seals, for example, but can be too complex for miniaturized connectors.